Other heparin-induced thrombocytopenia syndrome

This code describes a rare, immune-mediated adverse drug reaction to heparin, resulting in a significant drop in platelet count and an increased risk of thrombosis. It encompasses variations of heparin-induced thrombocytopenia (HIT) that do not fit the criteria for the more common, acute forms. This condition can lead to severe and life-threatening complications.

Use this code for documented cases of heparin-induced thrombocytopenia that present with atypical features or delayed onset, or when the specific type of HIT is not otherwise classifiable. Documentation should clearly indicate a causal link between heparin exposure and the thrombocytopenia, along with clinical evidence supporting an "other" or atypical presentation.

• Ensure documentation specifies "other" or atypical HIT, distinguishing it from acute HIT (D69.51) or HIT with thrombosis (I78.8).
• Always sequence this code after any codes for the underlying condition requiring heparin, if applicable.
• Look for specific mention of positive HIT antibody tests (e.g., PF4-heparin ELISA) or functional assays (e.g., serotonin release assay) in the medical record.